Greedy lab

I had a baby last year and had numerous blood tests via lancet in hospital, This was covered by medical aid and gap cover. They contacted me for R100 outstanding which I paid - after them making thousands from me. Recently I have been contacted to say my account is handed over - I made contact and sent them my email from Lancet with the statement and proof of payment and asked that someone call me urgently. Still no call and still getting legal messages! My next step will be the Ombudsman